Fix regex in jenkins-slave.sh to rewrite ci.bazel.io -> jenkins.
Fix regex in jenkins-slave.sh to rewrite ci.bazel.io -> jenkins.

Change-Id: Iab439615d64b1e3d6a289c034b6ca3ac865ace9f

bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration,bazelbuild/continuous-integration